SOLUTION: In the year 2000 Donald was 12 and his father was 40. In which year was Donald's father 8 times as old as Donald?

Algebra.Com
Question 394149: In the year 2000 Donald was 12 and his father was 40.
In which year was Donald's father 8 times as old as Donald?
Answer by Edwin McCravy(20056)   (Show Source): You can put this solution on YOUR website!
In the year 2000 Donald was 12 and his father was 40.
In which year was Donald's father 8 times as old as Donald?


Let the desired year be x years before 2000 or the year 2000-x.

x years before 2000 Donald was 12-x and his father was 40-x.

So we want 12-x to be th of 40-x.  To say that in algebra,

          12 - x = (40 - x)

Clear of fractions by multiplying both siades by 8

         96 - 8x = 8*(40 - x)

Cancel the 8 and the  and you have

         96 - 8x = 40 - x
             -7x = -56
               x = 8

So the year was 2000-x or 2000-8 or 1992, when Donald was 4 and his
father was 32.

Edwin
RELATED QUESTIONS

in 1984, my father was 3 times as old as me. in 2000, my father was twice as old as me.... (answered by stanbon)
Sarah is 1/3 as old as Donald. In 1 year, Sarah's age will be 3 years less than 1/2 of... (answered by josgarithmetic)
The average age of Donald, his wife and their two children is 23 years. His wife is just... (answered by Edwin McCravy)
In three more years, Danny’s father will be 2 times as old as Danny was last year. When (answered by josmiceli)
I do not understand at all Donald gave Louie a number of marbles to share with Dewey... (answered by josmiceli)
1n 2005,a father was 4 times as old as his son.in the year 2015,thrice the son's age will (answered by ankor@dixie-net.com)
a 48 year old man is two times as old as his son. How old was the father when he was... (answered by stanbon)
Nicole is half as old as Donald. The sum of their ages is 72. How old is Nicole, in (answered by passionn)
One year ago the father was 8 times as old as his son. Now, his age is the square of his... (answered by algebrahouse.com)